While DMD is characterized by the absence of dystrophin, mutations that result in the retention of a partly functional dystrophin gene product are characteristic for the less severe dystrophinopathy type, called Becker muscular dystrophy (BMD) (incidence: at least 1 in 18,450 male live births [5]). The gene discussed is DMD; the disease is neuromuscular disease caused by qualitative or quantitative defects of dystrophin.